How do pilots of big widebody planes know if their planes are lined up with runway when they take off?

Generally speaking, lining-up an airplane on a runway is a visual maneuver -

No difference between line-up of a Piper Cub or a Boeing 747 -

Yes, the compass is checked to verify alignment on the proper runway (QFU) -

Adjustments to alignment are made with nose wheel steering (rudder pedal or tiller) -

Above 60 knots or so, the rudder surface is effective - no need for steering -

Do not imagine your "flight sim game" to be same as a real airplane...!

You evidently are NOT a pilot -

The centerline of the runway is clearly marked.

By the time you get in the front seats of any airliner, you would have preformed thousands of takeoffs, every single one of them done by looking out the windscreen and visually tracking down the centerline.

Edit : Even in the largest "wide body" airliner, the pilot's position relative to the centerline does not vary much, at least laterally. You might be sitting higher off the ground, but the centerline is going to be within a few inches of being directly under your elbow. Cockpit size does not vary much - since there are controls and switches that have to be within easy reach of both pilots, both pilots seats are as close to the center console as possible. The distance that your head is from the centerline would vary only inches from even the smallest planes to the largest

You realize that the pilots of a widebody plane essentially still sit at the center of the plane, given that the pilot and co-pilot are only one arms length form one another?

They look out of the cockpit window and line up with the big white line down the centre of the

runway.

Follow the big white line that's painted down the middle of the runway.

We use a magical device, developed over many many years.

It is known as ''The Mk 1 Eyeball" Redundancy is built in, we have two of them.

An amazing piece of kit called a window.

FFS!!!

Update: Head location? Please tell me you're joking. Nobody can be this stupid.

look out the window.